Crystal structure of the quorum-sensing protein LuxS reveals a catalytic metal site
Crystal structure of the quorum-sensing protein LuxS reveals a catalytic metal site
复制标题
DOI：
10.1073/pnas.191223098
复制
发表时间：
2001-09-25
影响因子：
11.1
通讯作者：
Ludwig, ML
中科院分区：
文献类型：
--
作者：
Hilgers, MT;Ludwig, ML
细菌调节基因表达以响应细胞密度变化的能力被称为群体感应。这种行为涉及细胞外荷尔蒙类化合物的合成和识别，这些化合物被称为自身诱导剂。在这里，我们报道了来自枯草芽孢杆菌的一种自诱导合酶的结构，在1.6埃分辨率下(R-Free=0.204；R-Work=0.174)。LuxS是一种具有新折叠的同源二聚体酶，它结合了两个相同的四面体金属结合位点。这个金属中心由一个由两个组氨酸、一个半胱氨酸和一个溶剂分子配位的锌原子组成，使人想起在几种肽酶和酰胺酶中发现的活性部位。虽然由LuxS合成的自身诱导剂的性质不能从晶体结构中推断出来，但推测的活性中心的特征表明，LuxS可能催化小底物的水解性切割，而不是蛋白水解性切割。我们的分析代表了对基于结构的功能分配的测试。
The ability of bacteria to regulate gene expression in response to changes in cell density is termed quorum sensing. This behavior involves the synthesis and recognition of extracellular, hormonelike compounds known as autoinducers. Here we report the structure of an autoinducer synthase, LuxS from Bacillus subtilis, at 1.6-Angstrom resolution (R-free = 0.204; R-work = 0.174). LuxS is a homodimeric enzyme with a novel fold that incorporates two identical tetrahedral metal-binding sites. This metal center is composed of a Zn2+ atom coordinated by two histidines, a cysteine, and a solvent molecule, and is reminiscent of active sites found in several peptidases and amidases. Although the nature of the autoinducer synthesized by LuxS cannot be deduced from the crystal structure, features of the putative active site suggest that LuxS might catalyze hydrolytic, but not proteolytic, cleavage of a small substrate. Our analysis represents a test of structure-based functional assignment.